Conventionally, various proposals are given regarding radar apparatuses for detecting target objects in a manner that a detection image for a detection range is formed through transmitting radio signals to the detection range of a predetermined area and receiving reflection signals caused by the radio signals. As described in Patent Document 1, such a radar apparatus uses a pulse signal as the radio signal to be transmitted, and the pulse signal is transmitted continuously at a predetermined interval. Conventional radar apparatuses generally use magnetrons as oscillation amplifying elements for generating the pulse signals, based on a view that they can easily obtain a high electric power for transmission.